SUMMARY/ABSTRACT Preterm birth (PTB; childbirth <37 weeks) is responsible for approximately 35% of infant deaths in the U.S., and is an important cause of short- and long-term morbidity. The estimated annual societal economic cost of PTB nationally is more than $26 billion. PTB disparities are well documented, with racial/ethnic minority populations persistently experiencing higher PTB rates. Intermediary determinants, including individual and interpersonal level factors, and structural determinants such as healthcare, community and societal level factors, are posited contributors to racial/ethnic disparities. However, researchers have not examined how these interdependent and interacting determinants influence PTB disparities within a racialized social system. Such an understanding is needed to develop effective interventions. The candidate hypothesizes that inequitable customs, practices and laws in various sectors of society operate in self-reinforcing/correcting ways to maintain inequality. The functioning of these determinants is dynamically complex and cannot be studied via conventional statistical methods due to the interdependence of multi-level factors, inherent feedback processes and interactions between them, and time delays between ?exposures? and outcome. System Dynamics Modeling (SDM) is designed to study dynamically complex problems, and has been successfully used to inform policies regarding social determinants of health. The candidate is applying for this award in order to develop expertise in SDM. The training component of the award also includes formal/informal training in health equity measurement, health policy, and benefit-cost analysis. The research component of the award aims to address significant gaps in our understanding of how structural and intermediary determinants generate and perpetuate racial/ethnic PTB disparities, as well as inform strategies to address these disparities. Aim 1 is to identify pathways through which structural and intermediary determinants generate or maintain racial/ethnic PTB disparities. Aim 2 will build upon the foundational work of the first aim and develop a quantitative SD model of mathematical relationships representing the causal mechanisms. Additionally, this aim will test dynamic effects of healthcare sector interventions (progestogens and low-dose aspirin administration for women at risk for preterm delivery and pre-eclampsia). Aim 3 is to conduct benefit-cost analyses and simulate efficacy of the healthcare sector interventions. The candidate is a social and perinatal epidemiologist, well trained in diverse and complementary analytical tools of quantitative and qualitative methodology. The proposed training program supports the candidate?s long-term career goal to become a renowned investigator in health disparities research, with particular emphasis on understanding determinants of disparities in maternal and child health and the development and evaluation of effective interventions to reduce the disparities via a diverse toolkit of methodology, including systems science.